1. Field of the Invention
The present invention relates to a thin film transistor (TFT) board for a liquid crystal display device and a manufacturing method for a liquid crystal display device.
2. Description of the Related Art
A thin film transistor formed on a TFT board of a liquid crystal display device may be efficiently tested with an assist of light. More specifically, after electric charges are charged in a pixel electrode to turn OFF a thin film transistor, the thin film transistor is irradiated with light for testing. When the light enters a semiconductor layer of the thin film transistor, carriers are generated to increase conductivity. Note that, the light used here has an intensity level that does not cause the thin film transistor to turn ON if the thin film transistor is normal. Therefore, if the thin film transistor to be tested is normal, the thin film transistor remains OFF even when light is applied thereto. However, if turning ON of the thin film transistor is detected, it is found that the thin film transistor has defects.
Conventionally, there is known a structure in which a color filter or a black matrix is formed above the thin film transistor of the TFT board (see Japanese Patent No. 4152623).
When the color filter or the black matrix is formed above the thin film transistor, it is impossible to irradiate the thin film transistor with light. Therefore, the above-mentioned testing method is inapplicable.